Not Applicable
Not Applicable
The invention relates to a tool assembly for the manufacture of ring-shaped compacts using a rotary compression press.
A tool assembly of the aforementioned type has become known from DE 298 01 312. The transverse pin, which extends through the shank of the lower ram, which has a slot in this region, is disposed in a bore of the die insert. A tool assembly of this type is particularly advantageous if cylindrical and ring-shaped compacts are produced alternately. Any exchange of the die-plate may be completely dispensed with.
OE 257 844 has made known a tool assembly in which a transverse member to which the central pin is connected is pressed by a spring against a die-fixed shoulder. The transverse member extends through a transverse slot of the lower ram. In contrast to the above described tool arrangement, hence, the central pin is not kept stationary with respect to the die-plate.
It is the object of the invention to provide a tool assembly for the manufacture of ring-shaped compacts using a rotary compression press in which the central pin is adapted to be dismounted and mounted in a simple manner for reattachment in a reproducible position.
In the inventive tool assembly, the transverse pin is located in a ring or ring-shaped sleeve which, in turn, is disposed in a guide bore for the shank of the lower ram, thus forming a part of the guide bore. The guide bore is formed on a radial projection of the die-plate, such guide bore not constituting the only guide of the lower ram. Two bracket-shaped retaining clips are disposed on opposed sides of the lower ram wherein a longer leg abuts against the underside of the ring and a shorter, second leg is bent over the projection. A web interconnecting the leg is connected to the projection via a bolted joint in such a manner that it may be radially bolted on against the projection from outside. If this is done an appropriate shape of the projection and the legs of the retaining clip causes the longer leg to exert an axial pressure onto the ring towards the upper ram and the die, which causes the ring to be safely held in the corresponding recess in the bore of the projection. To attain such effect, it is required for the ring to protrude, at least to a minimal degree, from the guide bore at the underside of the projection.
By means of the design described, the central pin is adapted to be dismounted by disconnecting the bolted joint in a simple and sufficient manner so that another lower ram having a central pin may be installed in a simple manner.
Cooperation between the retaining clip and the projection or the die-plate is preferably such as to provide conically shaped surfaces which interact, while the bolted joint is being tightened, so as to press the inner leg of the retaining clip against the retaining ring of the transverse pin.
The transverse pin preferably is of a cross-section having the shape of an elongated rectangle, the transverse pin being disposed edgewise in the ring and the central pin. This enables the transverse pin to absorb large forces and makes it less susceptible to flexure.
In another aspect of the invention, a radial bore is disposed at the lower end of a recess which is below the projection and within the area of which the lower ram is exposed. Air may be blown into the recess from the interior of the die-plate through a radial bore in order to blow away dust which might accumulate in this area. This may be accomplished in a way that a stationary nozzle is disposed at the level of the radial bore and allows compressed air to be expelled therefrom either continuously or intermittently. If air is forced out impulsively a suitable control may be effected via the rotation of the die-plate.